Steganography and digital watermarking are powerful techniques for protecting intellectual property by embedding signatures and other information in audio, video and other digital media. Recognizing these signatures and verifying their integrity identifies intellectual property to prevent its misuse, detect its modification or generate royalties.
The study of steganography encompasses the practice of hidden or obscured messages in printed and visible works, and includes outright cryptography and other ciphers which render the media unintelligible. Unlike cryptography, however, steganographic techniques in general do not obfuscate the underlying media item, and therefore do not draw attention the way encryption does. Therefore, while steganographic implementations may inject either readily visible or more obscured artifacts in the underlying media item, they generally do not prohibit intelligible reception by the user, but rather continue to merely denote the source or origin of the media item. Conventional watermarks include visible markings and/or images currency, commercial instruments (checks), government IDs (e.g. driver licenses) and video broadcasts. A common property is that modification to generate a purported similar version (duplicate or unchanged original) is very difficult to perform without also modifying the watermark in a detectable manner, thus providing a level of security to the unmodified original.
Modern information security issues surrounding computer software devote much attention to malicious code. Malicious code is an executable addition to an installed program that, unbeknownst to the user, infiltrates the code for performing extraneous operations such as gathering personal information, launching an email barrage, or simply corrupting or destroying other files. Malicious code typically takes the form of a virus, worm or Trojan horse, each with subtle differences in operation and objectives, but having the common operation of modifying an existing code segment to introduce foreign executable software for performing unwanted operation.